Space telescopes have provided us with plenty of information about our Solar System, with Hubble and James Webb telescopes in the lead. Today, James Webb Space Telescope (JWST) remains the most advanced piece of equipment, with an aperture diameter of 6.5 m. However, space science does not stand still, and missions to develop optical telescopes with aperture diameters up to 20 m are already underway. And CubeSat cameras will play a major part in making these new advanced telescopes. But how exactly will CubeSat technology help with telescope building? Read on to find out.
Autonomous Assembly Reconfigurable Space Telescope Concept
Autonomous Assembly Reconfigurable Space Telescope (AAReST) concept is based on the idea that a multi-aperture space telescope could be assembled directly in orbit. Using CubeSats with advanced cameras would make it possible to create a large segmented primary mirror. Several CubeSat camera missions are already in progress. Right now, the primary participants are Surrey Space Centre (SSC), California Institute of Technology (Caltech), and Indian Institute of Space Science and Technology (IIST), but there eventually could be room for more global partners.
According to AAReST mission participants, the project is generally moving to the increased use of CubeSat camera technology because these imagers have already proven easy to configure directly in orbit and because they provide high-quality astronomic images.
What Cameras are Used in Space Telescopes?
The current configuration of AAReST presupposes using several CubeSat cameras based on several independent segments — two MirrorSats and one CoreSat. Mirror CubeSat cameras will be based on standard 3U CubeSat structures, while each standard CubeSat structure will carry a dedicated payload. Both imagers will be able to dock and undock automatically with the help of an optical electromagnetic system.
CoreSat camera components will be based on a tailored nano-satellite structure, similar to those of standard CubeSat units. The 9U CoreSat will carry Reference Mirror Payloads, similar to those of MirrorSats. This unit will also ensure in-orbit assembly as it will be equipped with a deployable carbon-fibre assembly system and additional astronomical imaging cameras.
CubeSat Camera and Top Mission Goals
The main idea behind this innovative CubeSat mission is that all three spacecraft components are fully independent and self-supporting. This carefully designed self-autonomy should help create higher-quality CubeSat images with the core camera’s frontal plane. The main idea behind this concept is that all mirrors used in imaging have to be manoeuvrable to change shape and focus, thus ensuring higher-quality CubeSat imaging. But what makes this technology concept so special? To answer this, we must first determine — how does a satellite take pictures, and how does this technology compare with space telescopes like Hubble?
Today’s satellites rely on sensors that can capture more information than human eyes. CubeSats assign a pixel value to any light reflectors their cameras can capture. Originally, cameras could only transmit black and white images, but today’s technology allows assigning colours to satellite bands. Space telescopes work very similarly, but their cameras are more like the ones we use every day on our smartphones — but on a greater scale, of course. The primary idea behind the AAReST project is to make use of both concepts while also ensuring greater cost-efficiency and more spacecraft autonomy in orbit. And this leads us to another question — how will the actual telescope be designed once CubeSat cameras demonstrate their value in this mission?
AAReST Design & Payload
Once assembled, the AAReST telescope will feature a large aperture consisting of multiple mirror elements, each about 10 cm in diameter. The telescope will operate in the visible band range of 465-615 nm wavelength. The narrow mirror configuration will ensure an aperture of 0.405 m, while a more wide-space assembly will provide a 0.530 m aperture.
Each assembled mirror allows minor position adjustments, which in turn, could lead to thermal distortions and a few alignment errors. Still, the overall CubeSat camera image quality should not be compromised. Another advantage of this project is that AAReST telescope, despite its large aperture, can rely on CubeSat cameras that can be easily produced today. For example, a CubeSat camera ranging from 2.2 µm to 5.5 µm should fully accommodate the needs of this innovative space project. The last but not the least important advantage of using CubeSat cameras is that they are very low-weight, which means spacecraft delivery to orbit will be more affordable.
Soon enough, the AAReST telescope in-orbit testing should begin, and within a few years, we will know exactly how valid this project is. On the whole, there is great potential, and even if certain adjustments to the technology are required, one thing is certain — CubeSat cameras will keep playing a major role in our space exploration and earth monitoring efforts.
